Secretary of State George P. Shultz said yesterday that "I think it's time" for King Hussein of Jordan to decide whether he is willing to enter the expanded talks with Israel proposed in President Reagan's Middle East peace initiative last Sept. 1.

Almost halfway through March, which has often been described as a crucial time for Hussein's decision, Shultz said: "Basically, I think it's time to move. I don't want to set a deadline or anything like that, but I think there has been a great deal of discussion. I don't know that there are more facts to be found."

Shultz spoke in an interview with The Washington Post as he entered a weekend of discussions with Israeli Foreign Minister Yitzhak Shamir and Lebanese Foreign Minister Elie Salem on a related aspect of the tangled Mideast dispute--negotiations on withdrawal of foreign armies from Lebanon. The secretary said there have been no prearranged deals that guarantee progress in the talks here, and he cautiously declined to project U.S. expectations.

Entering his ninth month as America's chief diplomat, Shultz brushed off a spate of criticism arising from several uncharacteristically blunt and combative remarks he has made in recent weeks.

"I don't feel that I've changed," he said in reference to speculation that there is a "new Shultz" whose manner and views resemble those of his predecessor, Alexander M. Haig Jr.

Discussing his most controversial statement, about "churchmen who want to see Soviet influence in El Salvador improved," Shultz indicated that he misspoke under questioning before a Senate subcommittee.

"I can get tired or needled, too, like anybody else. When you get hammered on day after day, you don't choose your words exactly right," he said. At another point, he said that if he had been a senator, he would have invoked the congressional privilege of revising his remarks.

The point he had been trying to make, Shultz continued, is that the Soviet Union "is not notable for its tolerance for freedom of worship" and that an extension of Soviet influence to places such as El Salvador "is basically antithetical to our values and those of the church." He said he had not intended to say that churchmen are purposefully trying to increase Soviet influence.

Casually dressed for a Saturday in the office, wearing a herringbone sport coat, a diamond-patterned sweater and slacks, Shultz seemed notably less relaxed than when he took over last July. Asked if he is happy in his job, he responded: "I didn't come here to be happy."

He said he had "a wonderful job" and "a great life" before as president of Bechtel Corp., the construction giant, but responded to Reagan's call because "It's a privilege to be in this job. It is one of those things where you have at least some chance to make an impact."

The Lebanon talks at the State Department this weekend represent the high-water mark of Shultz's personal involvement in Middle East diplomacy. He admitted to feelings of frustration about the slow pace of the Lebanon negotiations since a visit here by Shamir last October to explain Israel's opening bargaining position.

"It's a fair statement that it hasn't gone as fast as I and many others had hoped it might," Shultz said. He added, "Time is not a neutral factor in these things. As time passes and you don't accomplish things, there is always concern that there may be some deterioration somewhere."

As Shultz recounted it, Israel initiated Shamir's current trip out of a desire "to make sure we had a full understanding of their concern, particularly about security." The "prime function" of the U.S. side at this point is to listen, "and I intend to listen," Shultz said.

He was careful to avoid suggestions that he and Shamir might succeed in breaking the Lebanon deadlock in talks scheduled today and tomorrow and thus open the way to movement toward the wider peace process sought by Reagan.

"If anything else transpires, that's all to the good," he said. At another point, he added: "It is not a situation where there is some sort of prearranged deal . . . . That is not the situation at all . . . . The stated purpose is what I've said. We want to do that listening. And if additional things emerge, well certainly we'll work on it very hard."

It was his idea, he said, to invite the Lebanese government to send a senior representative "because we thought we should be sure that the same people who were exposed to the Israeli view of the situation also ought to hear directly from the Lebanese . . . whatever they wish to tell us."

Shultz and Foreign Minister Salem met for 1 1/2 hours yesterday afternoon. After the session, Salem told reporters that he will not meet Shamir here but expects to have further talks with Shultz. The minister said he believed a withdrawal accord can be achieved if all parties are "reasonable and pragmatic."

Reagan's two special Mideast envoys, Philip C. Habib and Morris Draper, also are participating in the talks with Shamir and Salem. The Israelis are understood to feel that Habib's mediation efforts have overemphasized the need for a quick withdrawal, and there has been speculation that Shamir wants to go over Habib's head and appeal to Shultz for more understanding.

Shultz said it is "very important" for everyone to know that Habib and Draper are not being circumvented.

U.S. officials have blamed the stalemate in Lebanon largely on Israel's insistence on maintaining forces and observation posts in southern Lebanon and its demand for normalized relations with the Lebanese. However, the ouster from the Israeli defense minister's post of Ariel Sharon, the most ardent advocate of those demands, has raised hopes that Shamir and others who believe in accommodation with Washington have become dominant within Prime Minister Menachem Begin's cabinet.

Israeli sources accompanying Shamir described his mission in roughly the same terms as Shultz. They said the Begin government feels it is time to renew its dialogue with the United States "at a very high level" and that Shamir wants to give Shultz a very detailed explanation of Israel's security concerns and its ideas about how they might be resolved.

"One should not get his expectations too high or speculate about breakthroughs even before the talks have started," said an Israeli official who asked not to be identified. "We come with an open mind but with very legitimate concerns."

The Israeli source said Shamir's desire to explain Israel's position to Shultz "should not be construed as a vote of no-confidence in Habib." He also stressed that Salem's visit here was "purely an American initiative" and said that, while Shamir would be happy to meet with him, the presence here of both foreign ministers should not be interpreted as an attempt to carry on indirect negotiations through Shultz.

In discussing Hussein and the Reagan initiative, Shultz noted that the king has been involved in complex negotiations with the Palestine Liberation Organization seeking its support for his entry into peace talks.

The United States has ruled out PLO participation in such talks but has recognized the need for inclusion in any Jordanian negotiating team Palestinians who are not PLO members but who will be recognized as spokesmen for West Bank and Gaza residents.

The secretary declined to say whether the PLO, in a recent policy declaration, left room for acquiescence in a negotiation headed by Hussein. "It's difficult to read what the view of the PLO is . . . . In this area, the messages seem to cover the spectrum of plus, minus and in between."

Shultz previously has expressed optimism that "one fine day" Hussein would decide to join the Mideast negotiations. His statement that the time has come for a decision appeared to reflect waning patience over lack of movement toward goals proposed by Reagan.

"For this move into the peace process to be successful, first King Hussein has to want to do it," Shultz said. "Second, I think everyone recognizes that there must be a Palestinian delegation . . . . We know it can be constructed. You can think of people. Whether or not it is constructed is the key."

On other subjects, Shultz said:

* Hortensia Allende, widow of assassinated Chilean president Salvador Allende, was denied a U.S. entry visa because the State Department contends that she is an official of the World Peace Council, which is on the attorney general's list of organizations controlled or influenced by the Soviet Union. Allende denied that she is a member.

"As a general proposition," Shultz said, "I lean toward exposing us to argumentation from any source as long as the source is labeled accurately . . . truth in packaging or whatever it is."

* He will consult Reagan about the U.S. position in the Euromissile talks in Geneva, following public appeals from Sen. Charles H. Percy (R-Ill.) and Italian Foreign Minister Emilio Colombo for a new U.S. negotiating offer. But Shultz gave no hint of his own opinion.

Shultz sidestepped questions about a controversial "hit list" of 18 arms control officials reportedly handed by U.S. chief strategic arms negotiator Edward Rowny to Kenneth L. Adelman, Reagan's nominee to be director of the Arms Control and Disarmament Agency.

Shultz' position is that questions on this are "beside the point" because Rowny issued a statement that the "informal talking points" on this subject do not represent his views.